[ALSA] Add even more 'const' to everything related to TLV

Mark TLV data as 'const'
Signed-of-by: Philipp Matthias Hahn <pmhahn@pmhahn.de>

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/include/sound/ad1848.h b/include/sound/ad1848.h
index c8de6f8..b2c3f00 100644
--- a/include/sound/ad1848.h
+++ b/include/sound/ad1848.h
@@ -185,7 +185,7 @@
 	int index;
 	int type;
 	unsigned long private_value;
-	unsigned int *tlv;
+	const unsigned int *tlv;
 };
 
 #define AD1848_SINGLE(xname, xindex, reg, shift, mask, invert) \